CVE-2019-12521
Medium
Description
An issue was discovered in Squid through 4.7. When Squid is parsing ESI, it keeps the ESI elements in ESIContext. ESIContext contains a buffer for holding a stack of ESIElements. When a new ESIElement is parsed, it is added via addStackElement. addStackElement has a check for the number of elements in this buffer, but it's off by 1, leading to a Heap Overflow of 1 element. The overflow is within the same structure so it can't affect adjacent memory blocks, and thus just leads to a crash while processing.
SeverityMedium
CVSS5.9
Exploit probability—
Product
Squid
PublishedApr 15, 2020
First seenApr 15, 2020
How to fix
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| squid-cache squid | 3.0 ≤ v ≤ 3.5.28, 4.0 ≤ v ≤ 4.7, 5.0 ≤ v ≤ 5.0.1 | — |
| canonical ubuntu_linux | 16.04, 18.04, 19.10, 20.04 | — |
| debian debian_linux | 9.0, 10.0 | — |
| opensuse leap | 15.1 | — |
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